Posturized bedding or seating product incorporating Bonnell coil springs with tapered middle portions

ABSTRACT

A posturized bedding or seating product is provided comprising a spring assembly made up of a plurality of parallel rows and columns of coil springs joined to each other. Each coil spring comprises a pair of knotted end turns with a plurality of conically tapered central convolutions therebetween. Certain sections of the product are made firmer than other sections by inverting the coil springs of one section relative to another section.

FIELD OF THE INVENTION

This invention relates to a posturized bedding or seating product in which certain sections are firmer than other sections of the product and the associated method of manufacturing such a product.

BACKGROUND OF THE INVENTION

Conventional bedding or seating products have a spring core made of a plurality of coil springs arranged into a matrix of rows and columns. Each of the coil springs has an upper end turn, a lower end turn and a plurality of central convolutions therebetween. The end turns may be knotted or unknotted. Coil springs having knotted end turns are known as Bonnell springs in the industry. The diameter of the end turns may be identical to the diameter of the central convolutions of the coil spring. Alternatively, the end turns of the coil springs may be of a larger or smaller diameter than the central convolutions of the coil spring. In some coil springs, the central convolutions taper from one end turn to the other. In other coil springs the central convolutions taper to a smaller diameter and then return to a larger diameter as they approach the end turns, thereby creating an “hourglass” shape. Typically, the coil springs are of the same height for ease of assembly.

The coil springs are usually connected or joined together by securing the end turns of adjacent coil springs to each other using helical lacing wire. The helical lacing wire encircles the end turns of adjacent coil springs, thus securing adjacent rows or adjacent columns of coil springs together. By lacing all of the coil springs together, a unitary spring core or spring assembly is made. Often one or two generally rectangular border wires are secured to the outermost coil springs of a spring core or spring assembly.

The spring core is commonly covered on one or both surfaces with padding and then wrapped in an upholstered material. Bedding or seating products made in this manner using identical coil springs typically have a uniform feel or firmness across the entire surface of the product due, at least in part, to the coil springs being identical and oriented the same direction within the spring core.

Other types of products are posturized, that is, different sections or zones of the bedding or seating product have different levels of firmness within the product. For example, the middle region of the mattress, which typically supports a person's torso, often requires a firmer less resilient support while other areas of the mattress which support the feet and head of a person require less support.

One known method of posturizing a spring unit has been to incorporate coil springs made of different gauge wire into the spring core. For example, rows of coil springs within certain sections or zones of the spring assembly are made of a heavier gauge wire than the springs incorporated into rows of the other sections or zones of the spring assembly. U.S. Pat. No. 6,173,464 discloses this concept, albeit with continuous bands of springs as opposed to individual springs. Due to the fact that different coil springs must be incorporated into the assembled spring core, the manufacturing cost of producing such a posturized product may be relatively high and assembly may be difficult.

Therefore, there is a need for a posturized spring assembly and associated method of manufacture which offers the advantages of posturization of the spring assembly without the higher manufacturing costs, production difficulties and inefficiencies associated with known posturized spring assemblies.

SUMMARY OF THE INVENTION

The present invention comprises a posturized bedding or seating product made of identical coil springs and its associated method of manufacture. The bedding or seating product comprises a posturized spring assembly, one or more pads and an upholstered covering surrounding the spring assembly and pad(s). The product is preferably two sided, but may be one sided.

The spring assembly or spring core within the product comprises a plurality of identical coil springs arranged in rows and columns and joined together with helical lacing wires at the end turns of the coil springs. Each of the coil springs comprises a first knotted end turn, a second knotted end turn and a plurality of central convolutions between the knotted end turns. In accordance with the practice of this invention, the central convolutions of the spring are conically tapered in diameter from the first knotted end turn to the second knotted end turn. Such springs are hereinafter referred to as conically tapered coil springs and are to be distinguished from cylindrical coil springs which have all of the central convolutions of approximately the same diameter or hourglass-shaped springs which have the central convolutions varying in diameter so as to form an hourglass shape from top to bottom.

The bedding or seating product typically has a longitudinal dimension and a transverse dimension, the longitudinal dimension being greater than the transverse dimension. However, the longitudinal dimension and transverse dimension may be identical in a square bedding or seating product. In the invention, the helical lacing wires may extend longitudinally or transversely, depending upon the desired effect.

At least one border wire may extend around the perimeter of the spring assembly of the bedding or seating product and be secured to select outermost coil springs. A first or lower border may be secured to the lower end turns of the outermost or perimeter coil springs. A second or upper border wire may be secured to the upper end turns of the outermost or perimeter coil springs. Alternatively, either border wire may be secured to intermediate convolutions of the outermost coil springs.

The spring core or assembly is divided into zones or sections of differing firmness, each of the sections comprising a plurality of rows or a plurality of columns of coil springs secured together. The zones or sections may extend from side-to-side (transversely) or from end-to-end (longitudinally) of the product.

Due to the conically tapered coil springs in one section, zone or region of the spring core being oriented differently than the coil springs in another section of the spring assembly, at least one section of the spring assembly has a “softer” feel when a load is placed thereon than at least one other section.

One aspect of the invention is a bedding or seating product which includes a spring core having a plurality of identical conically tapered coil springs. Each of the coil springs has a first knotted end turn, a second knotted end turn, and a plurality of central convolutions between the knotted end turns. The central convolutions taper in diameter from the first knotted end turn to the second knotted end turn. The spring core is divided into sections of differing firmness. All of the coil springs of at least one of the sections have the first knotted end turn above the second knotted end turn. All of the coil springs of at least one other section are inverted so as to have the first knotted end turn below the second knotted end turn. The bedding or seating product also includes padding located above the spring core and an upholstered covering surrounding the padding and the spring core.

Helical lacing wires join the coil springs together and can join them in adjacent rows or columns, i.e., extend laterally or longitudinally of the product. In addition, in some embodiments, a border wire is secured to some of the coil springs. The differing firmness sections can extend from one side of the product to the other side of the product, or, can extend from end-to-end in different embodiments. In some embodiments, the diameter of the knotted end turns of the coil springs are identical and in others, they may differ.

Another aspect of the invention is a method of manufacturing a posturized bedding or seating product having sections of different firmness. The method includes providing a plurality of identical coil springs arranged in rows and columns. Each of the coil springs has a first knotted end turn, a second knotted end turn and a plurality of central convolutions between the knotted end turns. The central convolutions are tapered conically in diameter from the first knotted end turn towards the second knotted end turn. The method also includes arranging the coil springs into rows and columns. The coil springs of several adjacent rows are oriented such that the first knotted end turn is above the second knotted end turn, and the coil springs of other adjacent rows are inverted and oriented such that the second knotted end turn is above the first knotted end turn. The method also includes joining the coil springs together with helical lacing wires.

Yet another aspect of the invention is a method of manufacturing a posturized bedding or seating product having sections of different firmness. The method includes providing a plurality of identical coil springs arranged in rows and columns. Each of the coil springs has a first knotted end turn, a second knotted end turn and a plurality of central convolutions between the knotted end turns. The central convolutions taper conically in diameter from the first knotted end turn towards the second knotted end turn. The method also includes arranging the coil springs into rows and columns. The coil springs of several adjacent columns or rows are oriented such that the first knotted end turn is above the second knotted end turn. The coil springs of other adjacent columns or rows are inverted and oriented such that the second knotted end turn is above the first knotted end turn. The method also includes joining the coil springs together with helical lacing wires.

These and other features of the present invention will be more readily apparent from the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a posturized bedding product made in accordance with the present invention comprising a spring assembly made of identical coil springs surrounded by generally rectangular border wires;

FIG. 2 is a perspective view of a coil spring made in accordance with the present invention in a first orientation;

FIG. 3 is a perspective view of the coil spring of FIG. 2 oriented in a second inverted orientation;

FIG. 4 is a diagrammatic top plan view of the spring core of the spring assembly of FIG. 1;

FIG. 4A is a cross-sectional view taken along the line 4A-4A of FIG. 4;

FIG. 5 is a diagrammatic top plan view of an alternative embodiment of spring core assembly made in accordance with the present invention;

FIG. 6 is a diagrammatic top plan view of an alternative embodiment of spring core assembly made in accordance with the present invention; and

FIG. 7 is a diagrammatic top plan view of an alternative embodiment of spring core assembly made in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to the drawings, and particularly to FIG. 1, there is illustrated a bedding or seating product in the form of a mattress 10. Although a mattress 10 is illustrated, the present invention may be used to construct any bedding or seating product. The mattress 10 comprises a spring assembly or core 12 having a generally planar top surface 14 in a top plane P1 and a parallel generally planar bottom surface 16 in a bottom plane P2. Covering pads 18 (only one being shown) may be located on the top and bottom surfaces 14, 16 of the spring core assembly 12. The covering pads 18 are usually formed from a cotton, felt, foam, or a synthetic fiber, but other materials can be used in other embodiments. An upholstered covering 20 or ticking encases the spring assembly 12 and the covering pads 18.

The mattress 10 has a height H defined as the distance between the top and bottom surfaces 14, 16 of the spring assembly 12. Similarly, the mattress 10 has a transverse dimension or width W defined between opposed side surfaces 22 and a longitudinal dimension or length L defined as the distance between the opposed end surfaces 24 of the mattress 10. The longitudinal dimension is illustrated as being larger than the transverse dimension of the mattress 10, although it is within the contemplation of the present invention that the longitudinal and transverse dimensions be identical, such as in a square product.

The spring assembly or core 12 is divided into two sections 26, 28 in the embodiment illustrated in FIGS. 1 and 4. Any number of sections readily apparent to those skilled in the art may be used in other embodiments, such as those illustrated herein with respect to FIGS. 5, 6 and 7. In the embodiment illustrated in FIG. 1, there is a first “soft” section 26 and a second “firm” section 28. The first section 26 is soft or has a “soft” feel because the coil springs 30 are constructed and oriented such that a predetermined amount of give or resilience exists within the springs 30. The second section 28 is a more firm section (firmer than first section 26) because the coil springs 30 are constructed and oriented such that a predetermined amount of resilience exists within the coil springs 30. The construction and orientation of the coil springs 30 are discussed in detail with respect to FIGS. 2-7.

Referring now to FIG. 2, a single spring 30 of the spring assembly 12 is illustrated. The coil spring 30 is usually formed from high carbon steel of between twelve and three-fourths and fifteen and a half gauge wire. However, those skilled in the art recognize that other gauges and materials can be used. The spring 30 has a first knotted end turn 32 and a second knotted end turn 34. These types of springs are known as “Bonnell” springs in the industry. The knotted end turns 32, 34 are formed by bending a wire into a generally circular shape. The illustrated knotted end turns 32, 34 have identical diameters, but other embodiments have varying diameters. Positioned between the knotted end turns 32 and 34 is a middle section 36. The middle section 36 includes a plurality of convolutions that taper conically from one end of the middle section 36 to the other. This conically-shaped middle section 36, which in the illustrated embodiment comprises three full convolutions, has its largest diameter convolution 37 connected directly to or terminating at the first end turn 32. The smallest diameter convolution 37′ is connected to the other or second end turn 34 by a connector section of wire 39. The end of the wire forming the end turn 32 terminates in a knot 38 that couples the end turn 32 to the next adjacent convolution and the end turn 34 terminates in a knot 40 that couples end turns 34 to the connector section 39. The knots 38, 40 are formed by bending or wrapping an end portion of the length of wire from which the spring is made around the convolution which is next adjacent the end turns 32, 34. Positioning or orienting the springs 30 as illustrated in FIG. 2 into a bedding or seating product results in providing more give or more resilience (softer feel) to the top of the bedding or seating product having springs so oriented as opposed to having the springs 30 inverted as illustrated in FIG. 3 because the larger turns or convolutions of the middle section 30 of the spring are at the top of the product. When the springs are inverted, the smaller diameter turns of the middle section 36 of the spring 30 are at the top and the top therefore has a more firm feel and is less resilient beneath the inverted spring when compressed from the top.

For example, in the embodiment illustrated in FIG. 1, coil springs 30 are placed inside the mattress 10 in different orientations. The coil springs 30 of the first section 26 are oriented as shown in FIG. 2, whereas the coil springs 30 of the second section 28 are oriented as shown in FIG. 3. In the coil springs 30 of the first section 26, the first knotted end turn 32 is located proximate to the generally planar top surface 14 of the mattress 10. Accordingly, the convolutions of the middle section 36 taper from a larger diameter to a smaller diameter as they move towards the generally planar bottom surface 16. The larger convolutions located close to the first knotted end turn 32 have a greater flexibility and deflect more than the smaller convolutions positioned close to the second knotted end turn 34. Accordingly, the first section 26 of the mattress 10 has more give and has a softer feel than the second section 28 of the mattress 10. As illustrated in FIG. 1, the springs 30 of the first section 26 of the product 10 are positioned in this manner, providing a “soft” feel.

Referring to FIG. 3, like reference characters are used to denote identical parts. The coil spring 30 is a spring identical to the coil spring 30 illustrated in FIG. 2 except that the position or orientation of the coil spring 30 has been inverted. The first knotted end turn 32 is now below the second knotted end turn 34 in the illustration. The convolutions of the middle portion 36 now taper from a large diameter to a smaller diameter as they extend upwardly. Positioning the coil spring 30 as illustrated in FIG. 3 in the mattress 10 results in more firmness and less resilience in a portion the bedding or seating product when the coil spring 30 is compressed from the top.

For example, placing the spring 30 of FIG. 3 inside the mattress 10 of FIG. 1 with the second knotted end turn 34 proximate to the top surface 14 of the mattress 10 provides a firmer top surface 14 than the bottom surface 16. The second knotted end turn 34 has smaller diameter convolutions positioned close to the knotted end turn 34 that will not deflect as much as the larger diameter convolutions. Accordingly, the mattress 10 will have a firmer feel. The second section 28 of the mattress 10 illustrated in FIG. 1 has springs 30 positioned in such a manner.

Referring now to FIG. 4, the spring core 12 of the mattress 10 of FIG. 1 is illustrated from a diagrammical top view. The mattress 10 of FIG. 1 is commonly referred to as a “his and her” mattress. The “his and her” name refers to the fact that there are two sections having different levels of firmness. Therefore, a couple can choose a mattress and custom design the levels of firmness to each of their personal preferences. The mattress 10 is divided into the first section 26 and the second section 28. The first section 26 has a soft feel, which is illustrated by the coil springs 30 having two closely spaced concentric circles representing the first knotted end turn 32 and the larger diameter convolution 37 of the middle portion 36 of a coil spring 30. In contrast, the second section 28 of the mattress 10 has a “firm” feel (firmer than the first section 26) illustrated by the springs 30 having two further spaced concentric circles representing the second knotted end turn 34 and the smaller diameter convolution 37′ of the middle portion 36 of the coil spring 30.

All of the springs 30 are joined together using the helical lacing wires 42. FIG. 4 illustrates the springs being laced together in columns that run parallel to the length of the mattress 10 or from end-to-end. FIG. 4 illustrates a border wire 44 surrounding the spring assembly 12 and secured to outermost coil springs 30 of the spring assembly 12, thereby providing edge support to the spring assembly 12, as is known in the art.

FIG. 5 illustrates an identical mattress 10′ to the one illustrated in FIG. 4 except that the helical lacing wires 42′ joining the springs 30 together extend in a transverse direction connecting adjacent rows, as opposed to adjacent columns of springs 30, the helical lacing wires 42′ extending from side-to-side. In addition, FIG. 5 illustrates a border wire 44′ surrounding a spring assembly 12′ and providing edge support to the spring assembly 12′. The mattress 10′ has a “soft” section 26′ and a “firm” section 28′ due to the orientation of the coil springs 30, as described above.

FIG. 4A illustrates how the springs 30 are positioned along one of the transversely extending rows of springs 30 illustrated in FIG. 4. The first section 26 of the mattress 10 has springs 30 positioned so that the first knotted end turn 32 is above the second knotted end turn 34. The first knotted end turn 32 is also proximate to the top surface 14 of the mattress 10. Due to the springs 30 having this orientation or positioning, the first section 26 has a soft feel. Conversely, the second section 28 has springs 30 inverted and positioned with the first knotted end turn 32 below the second knotted end turn 34. The second knotted end turn 34 and the smaller convolutions of the middle portions 36 of the springs 30 are proximate to the top surface 14 of the mattress 10. This positioning results in a firmer feel in the second section 28 compared to the first section 26.

FIG. 6 illustrates an alternate embodiment of a mattress 46 that has three sections of differing firmness. Identical reference characters are used to describe identical parts. The three sections alternate moving along the longitudinal dimension or length of the mattress 46. Adjacent columns of springs 30 also joined together using helical lacing wires 42″, the helical lacing wires 42″ extending along the longitudinal dimension of the mattress 46 (from end-to end). The first section 48 is a soft section. This soft section 48 as illustrated includes five transversely extending rows along the longitudinal dimension. This provides a soft area that will support either the head and shoulder or the feet and legs of a person lying on the mattress. The first section 48 therefore does not need as much resilience because the first section 48 is not supporting the heavier parts of the body. The second section 50 is a firmer section that includes six transversely extending rows of springs as illustrated. The second section 50 is firmer than the first section 48 to provide support for the upper and lower torso, the heavier parts of the body. Therefore, the second section 50 needs more resistance to support those heavy parts of the body. The third section 52 is identical to the first section, positioned only on the other end of the mattress 46. Together, the first, second and third sections 48, 50, and 52 provide a posturized mattress 46 that increases the support where it is needed most, in the middle of the product or mattress.

Referring now to FIG. 7, an alternative embodiment of a mattress 54 is illustrated. Identical reference characters denote identical parts. In this embodiment, the three sections are arranged alternatively along the transverse dimension or width of the mattress 54. The first section 56 is a firm section along the outer portion of the mattress 54. The second section 58 is a softer section arranged in the central portion of the mattress 54. In addition, the third section 60 is another firmer section. This positioning creates a soft central section 58 surrounded by the firmer sections 56 and 60. A consumer that desires a soft area to sleep in with outer support would prefer this arrangement.

Although I have described several preferred embodiments of our invention, I do not intend to be limited except by the scope of the following claims. 

1. A bedding or seating product comprising: a spring core comprising a plurality of identical coil springs, each of said coil springs having a first knotted end turn, a second knotted end turn and a plurality of central convolutions between said knotted end turns, said central convolutions tapering in diameter from said first knotted end turn to said second knotted end turn, said spring core being divided into sections of differing firmness, each of said sections comprising a plurality of said coil springs, all of said coil springs of at least one of said sections having said first knotted end turn above said second knotted end turn and all of the coil springs of at least one other section having the springs inverted to locate said first knotted end turn below said second knotted end turn; padding located above said spring core; and an upholstered covering surrounding said padding and said spring core.
 2. A bedding or seating product comprising: a spring core comprising a plurality of identical coil springs arranged in rows and columns, each of said coil springs having a first knotted end turn, a second knotted end turn and a plurality of central convolutions between said knotted end turns, said central convolutions tapering in diameter from said first knotted end turn to said second knotted end turn, said spring core being divided into sections of differing firmness, each of said sections comprising a plurality of said coil springs, all of said coil springs of at least one of said sections having said first knotted end turn above said second knotted end turn and all of the coil springs of at least one other section having the springs inverted to locate said first knotted end turn below said second knotted end turn.
 3. The product of claim 2 wherein said sections extend from one side of the product to an opposing side of the product.
 4. The product of claim 2 wherein said sections extend from one end of the product to an opposing end of the product.
 5. The product of claim 2 wherein all of the coil springs are the same vertical height.
 6. The product of claim 2 wherein said coil springs are joined together with helical lacing wires.
 7. The product of claim 6 wherein said helical lacing wires join coil springs of adjacent rows.
 8. The product of claim 6 wherein said helical lacing wires join coil springs of adjacent columns.
 9. The product of claim 2 further comprising at least one border wire secured to at least some of said coil springs.
 10. The product of claim 2 wherein said first and second knotted end turns of each of said coil springs of said spring core are of approximately the same diameter.
 11. A bedding or seating product having a longitudinal dimension and a transverse dimension, said longitudinal dimension being greater than said transverse dimension, said product comprising: a spring core comprising a plurality of coil springs arranged in transversely extending rows and longitudinally extending columns, each of said coil springs having a first knotted end turn, a second knotted end turn and a plurality of central convolutions between said knotted end turns, said central convolutions tapering in diameter from said first knotted end turn to said second knotted end turn, said spring core being divided into sections of differing firmness, each of said sections comprising a plurality of said coil springs, all of said coil springs of at least one of said sections having said first knotted end turn above said second knotted end turn and all of the coil springs of at least one other section having said coil springs inverted to locate said first knotted end turn below said second knotted end turn.
 12. The product of claim 11 wherein all of said coil springs are substantially identical.
 13. The product of claim 11 wherein said spring core further comprises helical lacing wires encircling adjacent end turns of adjacent rows of coil springs.
 14. The product of claim 11 wherein said spring core further comprises helical lacing wires encircling adjacent end turns of adjacent columns of coil springs.
 15. The product of claim 11 wherein said spring core further comprises at least one border wire.
 16. The product of claim 11 wherein said first and second end turns of each of said coil springs have the same diameter.
 17. A bedding or seating product comprising: a spring core comprising a plurality of coil springs arranged in transversely extending rows and longitudinally extending columns, each of said coil springs having a first and second knotted end turn of the same diameter and a plurality of central convolutions between said knotted end turns, said central convolutions tapering in diameter from said first knotted end turn to said second knotted end turn, wherein said spring core has at least one soft section and at least one firm section, each of said sections comprising a plurality of said coil springs, all of said coil springs of said at least one soft section having said coil springs oriented such that said first knotted end turn is above said second knotted end turn and all of said coil springs of said at least one firm section having said coil springs inverted and oriented such that said second knotted end turn is above said first knotted end turn.
 18. The product of claim 17 wherein said spring core further comprises helical lacing wires joining the end turns of adjacent coil springs.
 19. The product of claim 18 wherein said spring core further comprises at least one border wire secured to the end turns of the outermost coil springs of said spring core.
 20. The product of claim 17 wherein each of said coil springs is identical.
 21. A method of manufacturing a posturized bedding or seating product having sections of different firmness comprising the steps of: a) providing a plurality of identical coil springs arranged in rows and columns, each of said coil springs having a first knotted end turn, a second knotted end turn and a plurality of central convolutions between said knotted end turns, said central convolutions tapering in diameter from said first knotted end turn towards said second knotted end turn; b) arranging said coil springs into rows and columns such that the coil springs of several adjacent rows are inverted and oriented such that said first knotted end turn is above said second knotted end turn and the coil springs of other adjacent rows are oriented such that said second knotted end turn is above said first knotted end turn; and c) joining said coil springs together with helical lacing wires.
 22. The method of claim 21 wherein said rows alternate between inverted and non-inverted coil springs from one end of said product to an opposing end of said product.
 23. A method of manufacturing a posturized bedding or seating product having sections of different firmness comprising the steps of: a) providing a plurality of identical coil springs arranged in rows and columns, each of said coil springs having a first knotted end turn, a second knotted end turn and a plurality of central convolutions between said knotted end turns, said central convolutions conically tapering in diameter from said first knotted end turn towards said second knotted end turn; b) arranging said coil springs into rows and columns such that the coil springs of several adjacent columns are oriented such that said first knotted end turn is above said second knotted end turn and the coil springs of other adjacent columns are inverted and oriented such that said second knotted end is above said first knotted end turn; and c) joining said coil springs together with helical lacing wires.
 24. The method of claim 23 wherein said columns alternate between inverted and non-inverted coil springs from one side of said product to another side of said product. 